In the pharmaceutical and cosmetic fields there is a need of a lipid composition capable of incorporating lipids and pharmacologically or cosmetically active compounds and of being evenly applicable to biological surfaces, in particular in form of a thin coherent layer. The lipid composition should be of low viscosity to facilitate delivery, in particular by spraying. While the viscosity of such a composition can be substantially reduced by adding a volatile solvent, the initially formed unstable coherent layer comprising lipid, pharmacologically or cosmetically active agent and solvent should change to a stable coherent layer by evaporation of the solvent within a time period as short as possible.
While a high solvent content is beneficial by reducing viscosity it requires more time for evaporation. In other words, a high solvent content in a lipid composition of the aforementioned kind extends the time period during which the applied composition is comparatively unstable. By “comparatively unstable” is understood the stability of an applied composition comprising substantial amounts of solvent in respect of the stability of the same composition after evaporation of all or substantially all solvent. Examples of such compositions include compositions for topical administration of pharmaceutically active compounds and compositions for skin care. Compositions rich in lipids are prone to form liquid crystals, a formation which is accompanied by high viscosity caused by high degree of local order.
WO 01/87344 A1 discloses a pharmaceutical or cosmetic composition comprising one or more pharmaceutically or cosmetically active agent, one or more organosilicon compound based on oligomeric or polymeric diorganosiloxane, and one or more phospholipid. When applied to the skin, the composition of WO 01/87344 A1 penetrates directly within a short period of time into the skin or into the external layers of plants treated with it, so that it cannot be rubbed off since it is rapidly absorbed into the interior of the body. For embodiments intended to be used topically in humans or animals the organosilicon compound of the composition has a boiling point varying between 15° C. and 150° C. at ambient pressure.